1 #include "average.hpp" 2 3 #include <cassert> 4 5 std::optional<Average::averageValue> 6 Average::getAverageValue(const Average::averageKey& sensorKey) const 7 { 8 const auto it = _previousAverageMap.find(sensorKey); 9 if (it == _previousAverageMap.end()) 10 { 11 return {}; 12 } 13 14 return std::optional(it->second); 15 } 16 17 void Average::setAverageValue(const Average::averageKey& sensorKey, 18 const Average::averageValue& sensorValue) 19 { 20 _previousAverageMap[sensorKey] = sensorValue; 21 } 22 23 std::optional<int64_t> Average::calcAverage(int64_t preAverage, 24 int64_t preInterval, 25 int64_t curAverage, 26 int64_t curInterval) 27 { 28 int64_t value = 0; 29 // Estimate that the interval will overflow about 292471 30 // years after it starts counting, so consider it won't 31 // overflow 32 int64_t delta = curInterval - preInterval; 33 34 assert(delta >= 0); 35 // 0 means the delta interval is too short, the value of 36 // power*_average_interval is not changed yet 37 if (delta == 0) 38 { 39 return {}; 40 } 41 // Change formula (a2*i2-a1*i1)/(i2-i1) to be the 42 // following formula, to avoid multiplication overflow. 43 // (a2*i2-a1*i1)/(i2-i1) = 44 // (a2*(i1+delta)-a1*i1)/delta = 45 // (a2-a1)(i1/delta)+a2 46 value = (curAverage - preAverage) * 47 (static_cast<double>(preInterval) / delta) + 48 curAverage; 49 50 return value; 51 } 52